Process for manufacturing anodes.



EROGESS FOR MANUFACTURING ANODES.

No Drawing.

'0 all whom it may concern:

Be it known that I, PERCY CLAUDE CAM- nnoN Isnnnvooo, Ph. D., a subject of the King of Great Britain and Ireland, residing at Moss Cottage, Bushey Heath, Harts, England, have invented certain new and useful Improvements Relating to Processes for Manufacturing Anodes, of which the following is a specification.

This invention relates to a process for the manufacture of anodes for the electrolysis of aqueous solutions of metallic salts such as zinc, copper and nickel, and it has for its object to employ natural manganese ores for the purpose.

For the electrolysis of such solutions anodes are usually employed that are not attacked by the electrolyte or the products of electrolysis. It has been proposed to employ anodes made of peroxid-of manganese, and it has also been proposed to produce such anodes by heating nitrate of manganese within molds, by which anodes of peroxld of manganese are produced of a shape corresponding to the mold; but hitherto natural manganese ores have not effectively been employed.

The invention consists in the employment for the manufacture of such anodes of natural manganese ore after treatment for the removal of the impurities contained in it, and in the molding of this substance into the necessary shape in the manner herein-.

after described by the use of a suitable binding agent. For the purpose of the invention I find that high-grade manganese ores are suitable. but natural ores generally contain impurities such as iron. nickel, or cobalt, which hitherto has hindered their em ployment for the electrolysis of zinc sulfate and other aqueous solutions.

In carrying the invention into efi'eet I reduce natural high-grade manganese ores by grinding them into a finely divided condition, and I leach them in a solution of sulfuric acid or in-a solution of nitric acid, or in the solution of any substance which does not attack manganese peroxid. By this means the impurities contained in the ore, such as, for example, iron, nickel, or cobalt, are dissolved out. I then mix' the ore thus treated with a quantity of manganese nitrate (or instead I may spread over a layer of the 0T9 q ntity of the manganese nitrate) for p d that a proportion equivalent to per cent. of natural ore in the Specification of Letters Patent.

Patented June 22, I915.

Application filed May 17, 1913. Serial No. 768,377.

final product is effective; but 1 do not mix the ore with the full quantity of manganese nitrate. The manganese nitrate solution acts primarily .as a binder for the comminuted When heated and the nitrogen oxid Compounds driven off, the anode becomes a mass of the treated ore held together or agglomerated by the manganese oxid produced from the nitrate. This is slightly porous in character. To diminish or remove this objection, repeated treatment. with the nitrate solution is desirable. I first of all mix the ore with about one-half the necessary amount of the manganese nitrate in solution and work it into a paste on the mold or tray in which the anode is to be produced, and I distribute the paste in an even layer over the mold. I then heat this mixture 011 the mold or tray to a temperature of from 120 to 200 deg. C. until the water and the oXids of nitrogenare completely evolved. Upon the massor cake thus vproduced I spread the remaining part of the necessary quantity of nitrate solution and the mass or cake on the mold or tray is again submitted to a temperature of from 120 to 200 deg. C. until the oxids of nitrogen are removed. A still further quantity of the manganese nitrate may then be spread over the cake for its impregnation. that is. if the necessary quantity has not already been used, or a further quantity of ore mixed with manganese nitrate. Thus the anode may be built up by repeated subjection to heat of the ore mixed or impregnated with manganese nitrate.

It will be understood that the quantity of nitrate solution may be applied in anv num ber of stages as may be required. and that further quantities of ore mixed with nitrate may be added to build up the anode: but I prefer to apply the nitrate solution in con stant proportion. that is to say. so that the final product shall contain a. definite proportion of the natural ore, it being necessary to impregnate the cake or partiall formed dense and coherent by theperoxid of man-- ganese which is produced on the heating of may, after being washed in water to remove '"any adherent powder, be used as an anode without any further treatment. In the use of such anodes no impurities pass into the electrolyte.

What I claim as my invention and desire to secure by Letters Patent is l-. A method of producing anodes which comprises comminuting natural manganese dioxid ore, subjecting said ore to treatment with sulfuric acid under conditions effective .to remove all metallic compounds present other than manganese compounds, mixing the treated ore with. a solution of manganese nitrate'to form a paste, molding, drying, and heating to remove nitrogen compounds.

2. A method of producing anodes which comprises comminuting natural manganese dioxid ore, subjecting said ore to treatment with a solvent indifi'erent to manganese dioxid but capable of removing other metallicv compounds present, mixing the comminuted ore' so treated with a solution of manganese nitrate in quantity about onehalf the necessary amountto make the anode comprises comminuting natural manganese dioxid ore, subjecting said ore to treatment with sulfuric acid under conditions eifective to remove all metallic compounds present other than manganese compounds, mixing the treated ore with a solution of manganese nitrate to form a paste, molding, drying, and heating to remove the nitrogen compounds from the nitrate, and saturating the anode so produced repeatedly and drying and heating to produce a dense coherent article. 7

4. A method of producing dense coherent electrodes ofpure manganese diozrid from manganese ore, which consists in comminut- 'ing the ore, leaching with a suitable agent to secure the removal of iron, nickel and cobalt impurities, mixing the leached ore with a solution of manganese nitrate to make a paste, molding, drying, and heating to drive off nitrogen oxids, and repeatedly soaking the .electrode with a solution of manganese nitrate, drying and heating, until the pores thereof become filled and it be comes dense and hard. e

In testimony whereof I have hereunto signed my name to'this specification in the presence of two subscribing witnesses.

PERCY CLAUDE CAMERON ISHERWOOD. Witnesses:

Ronnnr OWEN HUGHES, HERBERT D. J AMESON. 

